1. Field of the Invention
The present invention related to an error variance detection method of CAN communication system and a CAN communication system.
2. Description of the Related Art
Recently, various electric control apparatus (ECU) are combined with a vehicle. The electric control apparatus are connected to one common network bus that includes one or two wires those are disposed along a vehicle body and is a type that connects desk top PCs of an office such that wiring thereof and production cost are dramatically reduced in a vehicle. This network is called a CAN controller area Network.
The electric control apparatus that are used in a CAN communication are connected to one common network bus and each control apparatus uses a CAN controller included in the electric control apparatus to receive and transmit independent control information such that it can optimally maintain the condition of the vehicle. Also, the electric control apparatus re-transmit or ignores the received signal, if a bit error or a form error is generated from a message about the received/transmitted control information. Therein, the error can be generated when the reception and the transmission of the message is not performed by a failure of a CAN controller or a short circuit/a disconnection of a CAN communication line, and the error or the failure can be called “CAN communication error”. In this configuration, a conventional diagnosis device is connected to a Can bus line and monitors a CAN message or an error frame that is transmitted or received between electric control apparatus those are connected to a CAN bus so as to detect a CAN failure or error.
However, when a CAN communication error is generated during the reception/transmission between electric control apparatus, a CAN controller and a CAN controller that detects the failure or error repeatedly transmits an error frame to deteriorate the performance of the network and the CAN communication bus line can become not available. That is, a conventional diagnosis device is difficult to diagnosis a condition of a CAN controller that performs a substantial CAN communication or a condition of software that is related to a CAN communication Due to an inoperative condition of a CAN communication bus line, when a CAN communication error is generated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.